Over-temperature protection devices



Feb. 19, 1957 s. H. REITER 2,781,769

OVER-TEMPERATURE PROTECTION DEVICES Filed Nov. 14, 1955 Adam;

r we United States Patent 2,781,769 OVER-TEMPERATURE PROTECTION DEVICES Sydney H. Reiter, Elizabeth, N. .l.

Application November 14, 1955, Serial No. 546,407

' 7 Claims. Cl. 137-74 The present invention relates to a novel and improved device to protect against the overheating of furnaces, ovens, vats, enclosures of all kinds, pipes and other equipment, and if desired, may be used in fire alarm systems. These uses are given as examples where this invention may be employed.

The principal object of this invention is to provide an over-temperature protection device of novel and improved construction having a new mode of operation, affording easy replacement of a fusible member which it includes and easy resetting after such device has been called upon to do its work.

A further object thereof is to provide a novel and improved protection device of the character mentioned, to keep various equipments and apparatus safe from damage which might be caused by overheating, or safe from fire; such device being of simple construction, reasonably cheap to manufacture, easy to use and eflicient in carrying out the purposes for which it is designed.

Other objects and advantages will become apparent as this disclosure proceeds.

I will now give a brief description of this invention and then will set forth the same in more detail.

Essentially, the device consists of a tubular member which is closed at one end by a replaceable fusible plug. The other end of the tube is closed by a movable member held tight on such tube end by the pressure of the atmosphere, because the tubes interior is a vacuum. This movable member is spring-biased for movement away from the tube end it closes, but the strength of such spring action is less than the force of the atmospheric pressure. Said tube is preferably removably mounted to extend with its fuse end into the enclosure to be protected. Should the temperature within said enclosure rise above a predetermined degree, the fuse will melt, causing an inrush of air into the tube and a consequent movement of the movable member away from the tube. Carried with the tube is either a switch controlling an electrical circuit or a valve controlling a fuel supply for instance. Movement of said movable member shifts the operating element of such switch or valve whereby an electrical circuit is actuated or the valve closed for instance, or an electrical circuit is made inactive or a valve is opened, depending upon the means used to stop the heat source. Where use of this device is made in a fire alarm system, the closing of a circuit may operate .an audible and visible alarm and if desired may bring a sprinkler system into action. My present invention concerns itself only with the actuation of the initial switch or valve upon a predetermined rise in'temperature, so I will now give a detailed description and explanation thereof.

In the accompanying drawings forming part of this specification, similar characters of reference indicate corresponding parts in all the views.

Fig. 1 is a perspective view of a device embodying ,the teachings of this invention.

2,781,769 Patented Feb. 19, 1957 I as Fig. 2, showing a slightly modified construction.

In the drawings, I have shown one form which my invention may assume. The numeral 15 designates an elongated tube which may be of stainless steel or other suitable corrosion-resistant material. This tube carries a receptacle 16, into which, one end of said tube extends. The receptacle, preferably has a removable cover 17. Loose against the exterior end of the tube 15, is a washer 18, the-hole of which is counterbored on the exposed face thereof to provide a seat for the disc 19 of a button 20. Thus button may also have an integral hub 21 which extends through the hole in said washer 18. A ferrule cap 22 detachably mounted on the exterior end of the tube 15 in any suitable way, as for instance by being threadedly engaged thereon, holds the button 2%) against the washer 18 and said washer against the exterior tube end, whereby said tube end is hermetically sealed. Said button may be separate from the washer and the hole 23 in the ferrule cap is slightly smaller than the disc U so that the inward flange 22 of the cap slightly overlaps the perimetrical zone of the said disc.

Against the other end of the tube 15, there is a loose disc or plate 24 having an apron 24' which is in telescopic sliding relation with said tube. When the interior of the tube is vacuum, it is evident that disc 24 will be tight against the tube end which it covers because of the action of the atmospheric pressure. In fact, said plate 24 is part of a sort of valve which is urged to open condition because of the stressed compression coilv spring 25, acting to shift said plate away from the tube end. The strength of such spring is of course less than the action of the atmosphere. The receptacle 16 carries a valve means or an electrical switch indicated at 26; the operating member 26 of such valve or switch, being in the path of said plate or cover disc 24.

The button 20 is of fusible material of the character that it will melt when subjected to a predetermined temperature which is the ultimate safe operating temperature for the apparatus being protected. Now assuming that the device of Fig. l is mounted so that the tube 15 thereof extends into the interior of an enclosure in apparatus to be protected or otherwise associated with such apparatus so that the tube 15 shall be subject to an operating temperature and assuming that the interior of tube 15 is vacuum so of course plate 24 will hermetically seal the tube end it is at, then, if the tube and hence the fusible plug becomes subjected to an unsafe temperature, said plug or button 243 will melt, causing an inrush of air into the tube and plate 24 will move away from the tube end it covers and thereupon shift the operating member 26 to operate the switch or valve means 26 thereby bringing into play mechanism (not shown) to halt the operation of the apparatus protected, sound an alarm or perform any other desired function.

It is to be noted that by use of vacuum in the tube 15, there is a total absence of any pressurizing gas in the tube and thus a pressure increase within the tube due to heating of such gas is prevented and a premature bursting of the fusible button 2% is obviated. Undoing of the vacuum will cause a pull to rupture the button 20 abruptly at its flow point instead of giving away slowly as the flow point is approached. This affords an accurate and reproduceable calibration of the device set forth herein. Further to be noted is that the fusible button 20 is easily replaced and offers a fixed calibration point for the device.

To provide the vacuum in the tube 15 for setting and resetting the device into operative condition, an exhaust pump may be applied to an open nozzle on the plate 24 which can then be sealed in any suitable manner to form a closed teat as at 24 or a valve 27 may be employed as part of Said plate 24 in tubing communicative with the interior of the tube 15. Said valve may be in a branch to said tube at say line A, which is easily understood without further illustration.

Upon rupture of the fusible button 20, the device is removed from its installation, the fusible button replaced and the vacuum condition within the tube 15 again effected. The device is now again ready for use.

This invention is capable of various forms and numerous applications without departing from the essential features herein disclosed. It is therefore intended and desired that the embodiment described be deemed illustrative and not restrictive and that the patent shall cover all patentable novelty herein set forth; reference being had to the following claims rather than to the specific description herein to indicate the scope of this invention.

I claim:

1. In a temperature-responsive device adapted for the control of the operation of certain mechanism, the combination of a tubular member, a fusible element and a closure element, both carried by said tubular member in spaced relation lengthwise therealong whereby the interior of the tubular member between said elements is closed by said elements; the fusible element being in fixed position on said tubular member and the closure member being held against movement towards the fusible element but free for movement away therefrom, a means for producing a vacuum in the interior of the tubular member between said elements; the closure element being exposed to the atmosphere and the fusible element having the character that it will melt when subjected to n predetermined temperature and a means having an operating element which when shifted, is adapted to control the actuation of the certain mechanism; said operating element being arranged that it will be shifted upon movement of said closure .element away from said fusible element.

2. The temperature-response device as defined in claim 1, wherein the closure element is positioned bearing against one end of the tubular member and including means on the tubular member, releasably holding the fusible element.

3. The temperaturerresponsive device as defined in claim 1, including spring means urging the closure element away from the fusible element; the strength of said spring means being less than the action of the atmosphere against said closure element.

4. The temperature-responsive device as defined in claim 1, wherein the mentioned means having the operating element is an electrical switch.

5. The temperature-responsive device as defined in claim 1, wherein the mentioned means having the operating element is a valve.

6. The temperature-responsive device as defined in claim 1, including a washer having a counter-bored hole; said washer bearing against an end of the tubular memher and positioned so that the counterbore is away from the closure element and wherein the fusible clement lies in and is removable from said counterbore and closes the hole of said washer and including a ferrule screw cap threadedly engaged on such end of the tubular member; the flange of said ferrule cap bearing against at least the fusible element.

7. The temperature-responsive device as defined in claim 6, wherein the fusible member fills the counterbore and the hole in the washer and is removable therefrom.

References Cited in the file of this patent UNITED STATES PATENTS 2,150,858 Eggleston Mar. 14, 1939 

